package cn.example;

import java.util.UUID;

/**
 * @author July
 * @description
 * @create 2025-11-19 21:56
 */
public class Main {

    private final static int FRESH_MASK = 0xF;  // 15

    public static void main(String[] args) {
        long fresh = 43222222543536222L;
        fresh =fresh & FRESH_MASK;  // 按位与运算  取低4位
        System.out.println(fresh);
        UUID uuid = UUID.randomUUID();
        System.out.println(uuid);
    }
}
